Pulsating screen



W. J. HARTWIG PULSATING SCREEN Dec. 9, 1947.

Filed Sept. 15, 1944 2 Sheets-Sheet 1 w mmvrm BY w - ATTOE/VEVS.

m. m (24 f 'II I I l II III Patented Dec. 9, 1947 PULSATING SCREEN Walter J. Hartwig, Wausau, Wis, assignor to D. J. Murray Manufactur'ng (30., Wausau, Wis., a corporation of Wisconsin 1 Application September 15. 1944, Serial No. 554,189 1 2 Claims.

I The present invention relates generally to improvements in the art of screening, and relates more specifically to improvements in the construction and operation of diaphragm actuated fiat screens for fibrous pulp or the like.

The primary object of my invention is to provide various improvements in the details of construction of diaphragm actuated flat screen assemblages, whereby the construction is simplified, the manufacture thereof is expedited, and the efficiency is enhanced to a maximum.

It has long been common practice in the paper making industry, to utilize diaphragm actuated fiat screens for the purpose of treating fibrous pulp, and these screens are ordinarily arranged in groups within elongated vats. The individual screen decks or plates of these screen assemblages must frequently be removed from their normal moorings either for cleaning and renewal,

or in order to gain access to the underlying diaphragms; and the flat decks must also be properly positioned relative to the pulsation producing diaphragms and these diaphragms must be properly actuated, in order to insure uniform and most effective screening operation.

It is therefore a more specific object of my present invention, to provide an improved diaphragm actuated fiat screen assembly, which is simple and durable in construction and highly 'eifective in use.

Another specific object of the invention is to provide improved instrumentalities for mounting and for detachably securing flat screen decks to a support in proper position relative to their cooperating diaohragms, and in a manner whereb; the individual screen plates ma be quickly and conveniently removed and installed.

A further specific object of this invention is to provide a simplified combination of actuating mechan sm and diaphragm and screen plate mountings, whereby the diaphragms will most eifectively cooperate with the adjacent screen. decks so as to thoroughly and uniformly agitate the fibrous pulp and thus ra idly purge the foreign matter from the good fibres.

Still another specific object of the present in: vention is to provide an improved d aphra m actuated flat screen all parts of which are readily accessible for inspection, lubrication, and replacement of arts, various elements of which are interchangeably similar and of inexpensive construction, and which may be maintained in most efiic ent operating condition with minimum loss of time and expense.

These and other specific objects and advantages of the invention will be apparent from t -e following description.

Aclear conception of the features constituting my present improvements, and of the mode of constructing and of operating pulsating screens built in accordance with the invention, may be had by referring to the drawings accompanying and forming a part of. this specification, wherein like reference characters designate the same or similar parts in the various views.

Fig. 1 is an exploded perspective view of a fragment of my improved diaphragm actuated fiat screen assemblage, showing one of the deck frames bearing two of the duplex screen plates, and the cooperating seal strip, lifted from their normal positions in the vat;

Fig. 2 is a transverse vertical section through the assembled pulp screen and diaphragm actuating mechanism;

Fig. 3 is a longitudinal central vertical section through an end fragment of the same screen assemblage, showing three diaphragms, actuat ng mechanisms therefor, and screen deck assemblies cooperating therewith;

Fig. 4 is an enlarged central vertical longitudinal section through one of the diaphragm actuating and positioning mechanisms; and

Fig. 5 is a fragmentary section through a corner of one of the screen plates.

Referring to the drawings, the improved diaphragm actuated fiat screen assemblage shown therein, comprises in general, an elongated open topped vat B mounted upon a support I and communicating at one side with a flow box 8; a series of horizontal flexible diaphragms 9 forming the bottom of the vat 6 and being separated by transverse rigid partitions I ll; a screen supporting frame I I mounted within the vat 6 above each diaphragm 9; a pair of duplex screen plates I2 su ported upon each frame H and cooperating with adjacent plates l2 to provide a contin uous horizontal screen deck above the diaphragms 9; a continuously rotating shaft I3 journalled in bearings l4 mounted upon the vat support 1, and having an eccentric portion 15 disposed centrallv beneath each diaphragm 9; a connecting rod l6 connecting each eccentric portion IS with the upwardly adjacent dia hragm 9: and a stabilizer plate I! associated with each diaphragm 9 laterally adjacent to its actuating rod 15 and eccentric I5.

to permit free inspection of the lower portions of the diaphragms 9 and of the bearings and motion transmitting mechanism. The diaphragms 9 are preferably formed of highly flexible material such as sheet rubber, and have their peripheral edges firmly secured to the side walls of the vat I and to the adjacent partitions Ill so as to provide a liquid tight chamber it between each diaphragm and the corresponding screen deck plates. I2; and the central portion of each diaphragm 9 is clamped between upper and lower reinforcing plates I9, respectively. The transverse earth tions Itlare also formed of rust-resistant material, and are firmly secured to t'he siae walls of the vat 6 so as to produce a durable and rigid pulp confining tank.

The screen supporting frames II are of inter changeablysimilar and durable construction, and each of these frames I I consists of a rectangular outer frame having depending integral transverse end flanges 2 I, and a cross-brace .fo'rnletlintegral with the outer frame and alsoneviiig a depenii= ing integral flange 22. The side flanges 2I of the adjoining flanges I I eoect with the upper edges 6f the adjacent vat partitions m thriiii'gh in= verted U shap'ed sealing strips 23st) as'te segre= gate the chambers I8; and the 'oppdsite sidesof each frame II are provided eritontal flanges 24 adapted toeoeet with ledges 25 formed within the vat Band to be handy attached to these ledges 25 b'y means of studs 26 and nuts '21, see Figs. 1 and 2. Each of the horizontal end flanges 24 or each frame II isp'rpvideci with openings for receiving .the studs 26, and with threaded holes 28 for receiving lifting eye-melts 29, and these eye-bolts serve to effect lifting'and lowering of the frames II when the nuts 21 have been removed. The names I I may be thusfirnily secured to the vat 6 during normal use, by means of the studs zt end nutS 'Z'I; but may-else be quickly and readily applied b'r removed with the aid of the threadedhole's 28 and eye bclt's 29 The screen deck lates I2 formed in dllplek sets orpairs of suitable material end'witn'rows of slots or perforations, and these plates I2 are also of nterchangeably sir'nila'r construction. Each of the plates I2 has a transverse imperio rate central reinforcing strip 30, and is provided at its edges with a seriesof hbles 3I adapted for the reception or fiat=head screws '32. These screws 32 are adapted to be screwed into threaded sockets formed in the top of each frame I], as clearly shown in Fig. '1, and while the plates I2 are carried by and removable with the'iram'esl l, the may also be a plied or removed independently of their earner frames with the aid of the screws 32. The tops of all of the assembled screen plates I2 'a'r'esmooth and lie in the same horizontal plane, and the screen plates I2 are normally rigidly secured to the frames I I and are prevented from being distorted h'y th'e heayily reinforced supporting frames II with their stiffening flanges 2 I, 22, 24. In order to maintain a smooth other screening deck and to' eliminate oorne'rs'in 'WhiGh fibrS and other solid material might loose; it is desirable to nor ally conceal the rotruding studs 26 and nuts 21 which hold the frames ii in lace, by means of readily detachable se'al strips 33. These seal strips 3-3 are fnrfiidin seetitns approximately equal in leng'th' to the widths of the frames, and each seal strip 3'3 is attached to the adjacent Wall Of the vet Ii by means of inclined bolts 34 and has aplOh plates 35 attached there to by fiat headed screws 36', as illustrated in Figs.

1 and 2. The seal strips 33 with the apron plates 35 attached thereto, may be quickly attached to or removed from the vat 6, and when the seal strips 33 are in normal operating position, the apron plates 35 snugl engage the adjacent side flanges 24 of the screen deck supporting frames II and thus thoroughly conceal the studs 26 and nuts 21. The downwardly and outwardly inclined disposition of the seal strip attaching bolts .34 co-- acting with the oppositely inclined upper inner surfaces of the strips 33, forces the apron plates 35 into snug contact with the frame flanges 24 along the edges of the screen plates I2, thus insui'i'n'g most effective sealing.

While the flexible diaphragms 9 are disposed horizontal and parallel to the screen plates I2, these diaphragms must be distorted or flexed in order to pulsate the liquid through the screen slots or perforations during normal operation of the assemblage, and the flexing movement of the diaphragms 5 should be uniform throughout their areas so as to ihsiire uniform pulsation of the lidllid body over the entire screening area and also in order to prolong the life of the char phragms. The constantlyrotating drive shaft I3 with its eccentric portions :5 coactih'g with the aiephragniee through the connecting bars or rode It andplates is, as, will effectively fies;

these diaphragms, but will also tend to tilt the plates I9, '20 thus producing unequal deflection ondistorti'o-h of the diaphragm sheets; and in order to prevent this undesirable tilting and line'olual deflection and to maintain the diaphragms parallel to the plates i2, 1 have provided a stabilizer or steady plate I? for each diaphragm 9. The upper ends of the connecting rods I6 are secured to the corresponding lower diaphragm lifter plates at by means of bolts 37 and intervehing rubber sheets 38, 39 which are spaced apart by slip plates B6, and the lower ends of these rigid rods It eoeet with the adjacent eeeentrie portions I5 of the shaft I3 through anti friction or ball bearings GI confined within e'ccentric housings 4.2, see Figs. 2, 3 and 4. The main shaft bearings It which are mounted upon the support I, are also preferably of the anti- I friction or ball bearing type, and all of these hearings I4, AI should be formed to accommodate slight deflections or misalinements between the various driving elements.

Each of the stabilizing plates I? has its upper eXtTelTli'ty WldellEd allcl rigidly attached to the corresponding lower diaphragm lifter plate 26,

while its lower narrower end is firmly attached by bolts 43s to the outer oscillating or swingin end of a relatively long horizontal leaf spring as. The opposite end or (iach le'a'f spring M is rigidly attached to the main support I by mean; of a bracket 35 and bolts ie, and the plates I? should be relatively stiff and should also be disposed parallel to the adjacent connecting rods it. During pulsation or vibration of the diaphragms 9 by the 'CCe'lltl'l Cs and (lbflflebtlhg I'OtlS, the leaf SD'I'iI'lg'S M Will be vibrated through the Stabilizer plates I'l, and sincethe lower ends of these plates are rigidly attaCheCl to the vertically oscillating provide for uniform purging of the pulp, and all parts of the actuating and stabilizing mechanisms are freely accessible at all times through the large opposite side openings 41 in the main support 1, see Fig-2.

During normal operation of the improved screen assemblage, the vat 6 should be supplied with an abundance of liquid pulp covering the screen deck, and the main shaft l3 should be constantly rotated at a suitable speed. The antifriction bearings I i, 4! should be amply lubricated, and as the shaft 13 rotates it revolves the eccentric portions I5 which coact with the adjacent diaphragms 9 through the connecting rods [6 and plates I9, 20, $8, 39, 40 to rapidly reciprocate or vibrate the flexible diaphragms 9 and to thereby pulsate the body of liquid pulp within the vat 6 through the screen slots or perforations formed in the deck plates I2. During this reciprocation of the diaphragms 9, the stabilizer plates ll effectively function to prevent undesirable tilting or distortion of the individual diaphragm sheets, and to insure most efiicient cooperation of the diaphragms Q with the adjacent screen plates [2 which are rigidly fixed above the successive pulsating compartments H! by the ribbed or flanged frames ii. The duplex screen plates l2 while being firmly held in place during normal o eration, may be quickly and conveniently removed either in pairs by releasing the seal strips 33 and aprons 35 and thereafter removing the adjacent frames i I, or individually by merely removing the fastening screws 32; and the seal strips 33 and aprons 35 cooperate with the countersunk fiat headed screws 32 to provide a flat and unobstructed horizontal screening deck. The seal strips 33 and aprons 35 moreover effectively protect the studs 25 and nuts 2'! and prevent foreign matter from lodging or collecting thereon, thus providing a simple but highly effective screening assemblage which may comprise any desired number of individual screen units.

From the foregoing detailed description, it will be apparent that my present invention provides a simple, compact and durable diaphragm actuated fiat screen especially adapted to purge liquid pulp or the like, which is highly efficient in operation, and all parts of which are readily accessible for inspection, repair and replacement. The flat screen plates [2 are firmly but detachably maintained in horizontal alinement, and the ad jacent diaphragms 9 are effectively stabilized and maintained in proper position relative to the screen plates E2, in a manner which will assure uniform pulsation of the liquid throughout the areas of the successive segregated compartments IS. The driving shaft l3 may also be formed in sections connected by suitable couplings 51! as indicated in Fig. 3, so that an desired number of the improved screening units may be provided dependent upon the screening capacity required, and the partitions IS and sealing strips 23 coact with the end flanges 2| of the frames H to eifectively segregate the successive pulsating chan1- bers l 8 from each other.

The stabilizer plates ll cooperate with the cocentric portions i5 and connecting rods to provide simple individual drives adapted to produce smooth but effective actuation of the diaphragms 9 and to maintain these diaphragms substantially parallel to the adjacent screen deck. and the flanged frames firmly retain the screen plates 12 in pro-per position while still providing for convenient removal thereof. These frames ll may be quickly removed together with the structure may obviously be manufactured at moderate cost and maintained in efficient operating condition with minimum attention and expense.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise mode of use, herein shown and described, for various modifications within the scope of the appended claims may occur to persons skilled in the art.

I claim:

1. In a pulsating paper pulp screen, a liquid confining vat having therein a series of segregated compartments, a flexible horizontal diaphragm spanning the bottom of each compartment, each diaphragm having a central rigid reenforcing plate secured thereto, a rigid open frame mounted upon said vat above each compartment, a screen plate mounted upon and spanning each of said frames to provide a continuous horizontal screening deck extending across the tops of all of said compartments, clamping means detachably connecting each screen plate to its supporting frame, other clamping means connecting each of said frames to said vat, sealing strips detachably secured to said vat and concealing said other clamping means, an eccentric revolvable about a horizontal axis centrally beneath each of said diaphragms, a rigid rod connecting each of said eccentrics directly with the corresponding diaphragm reenforcing plate, an approximately horizontal leaf spring disposed closely adjacent to and beneath each of said eccentrics, each spring having one end fixedly secured while its opposite end is freely vertically deflectable, and a rigid stabilizer plate connecting the defiectable end of each leaf spring with the corresponding diaphragm reenforcing plate.

2. In a pulsating paper pulp screen, a liquid confining vat having therein a series of segregated compartments, a flexible horizontal diaphragm spanning the bottom of each compartment, each diaphragm having a central rigid reenforcing plate secured thereto, a rigidopen frame mounted upon said vat above each compartment, a screen plate mounted upon and spanning each of said frames to provide a continuous horizontal screening deck extending across the tops of all of said compartments, clamping means detachably connecting each screen plate to its supporting frame, other clamping means connecting each of said frames to said vat, sealing strips detachably secured to said vat and concealing said other clamping means, an eccentric revolvable about a horizontal axis centrally beneath each of said diaphragms, a common horizontal shaft for rotating all of said eccentrics, a rigid rod connecting each of said eccentrics directly with the corresponding diaphragm reenforcing plate, an approximately horizontal leaf spring disposed closely adjacent to each of said eccentrics beneath said shaft, each spring having one end fixedly secured while its opposite end is freely vertically deflectable, and a rigid flat stabilizer 7 I 8 plate connecting the defiectable end of each leaf it spring with the corresponding diaphragm re- UNITED STATES PATENTS enforcing plate, the upper and lower ends of said Nu e Name Date stabilizer plates being rigidly attached to the ad- 234,719 Finder 61; a1 1380 jacent diaphragms and leaf springs. '5 Baker t a1 Apr. 18 1393 WALTER J. HARTWIG. 7 6,150 Lovejoy July 26, 1904 2,161,989 Waterous June 13, 1939 REFERENCES CITED 2,345,364 Spafiord Mar. 28, 1944 The following references are of record in the file of this patent: 10 

